How do you simplify # 8sqrt63 - 5sqrt7#?

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Answer 1 · 2018-05-21T02:29:53

#19\sqrt7#

#8\sqrt(63)=8\sqrt(9*7)=8\sqrt(\color(red)(3*3)\cdot7)#
#=(8*\color(red)(3))\sqrt(7)=24\sqrt7#

#\therefore8\sqrt(63)-5\sqrt7=24\sqrt7-5\sqrt7=19\sqrt7#

Answer 2 · 2018-05-21T02:32:36

#8sqrt63 - 5sqrt7=8*sqrt(9*7)-5sqrt7=19sqrt7#

show that:

#color(red)[sqrt(a*b)=sqrta*sqrtb]#

#8sqrt63 - 5sqrt7=8*sqrt(9*7)-5sqrt7#

#8*sqrt9*sqrt7-5sqrt7=8*3*sqrt7-5sqrt7#

#24sqrt7-5sqrt7=19sqrt7#